Are there really tongue-eating parasites?

Answers

Yes. There’s a species of isopod–a type of louse the same family as pillbugs, and looking very similar but much larger–that will crawl into a fish’s mouth, eat it’s tongue and then live in the mouth as a sort of replacement tongue, eating some of the food as it comes in. Amazingly, the fish survives this experience and seems to live on with only a minor impediment. This animal was known to exist, but is very rare to find; this specimen was found off the coast of the islands of Minquiers in Great Britain. It is harmless to humans, except for the bite it is known to deliver if you stick your finger in a fish’s mouth.

Yes. The Cymothoa exigua is a parasitic crustacean. Known as the tongue-eating louse, this 3-4 cm long parasite attacks the spotted rose snapper fish. It enters through the gills and attaches to base of the host’s tongue, sucking on its blood until the tongue atrophies and falls off. The only known species to functionally replace a host’s organ, the louse acts as the tongue by attaching to the remains of tongue-controlling muscles. Thus insuring that the fish stays alive and can’t get rid of it, the louse feeds on fish food or mucus.